Each video will appear on Facebook for a full day, and cost advertisers between $1 million and $2.5 million per day, say the sources. The ads can only be targeted by age and gender, and the launch of this product was apparently pushed back at least twice by Facebook founder Mark Zuckerberg, who wanted to make sure the videos didn’t “taint” the user experience at Facebook.

If history is any guide, these new ads will face much derision, and adjust their presentation according to the data on usage patterns that the company is constantly gathering. The company has in the past retracted or modified new features that were deemed too intrusive by users, such as the Beacon advertising platform that allowed advertisers to publish directly to a user’s news feed the things that person had purchased on their sites. Zuckerberg subsequently called Beacon a “mistake,” but advertisements from outside websites that are tracking users are now an important part of Facebook’s revenue, so in a way Beacon lives on in a highly modified form. We’ll see if outcry over Facebook’s video ads leads to a similar modification after they roll out.